Dental ha ndpiece



`uary 7, 1896, No. 552,669.

UNITED STATES i PATENT OFFICE.

JOHANNES TH. PEDERSEN, AOE wOoDsIDE, NEW YORK.

e DENTAL HANDPIECE.

SPECIFICATION forming part of Letters Patent No. 577,063, dated February 16, 1897.

Application iiled January 6, 1898. Serial No. 574,423. (No model.)

provement upon the device shown and described in Letters Patent granted to me J an- In said patent the pressure endwise that causes the tool-holder to grasp the tool is derived principally from a toggle movement.

In my present invention, as in the aforesaid patent, I employ a handpiece wherein the tool is held by the internal mechanism in the straight normal condition and released by a direct lateral pressure of one hand upon the handpiece while holding the same, which pressure detlects the parts and alters the alinement of one part to the other and produces an elongation, which releases the grip upon the tool, said grip being restored by the return of the parts to a normal condition. In the present instance the tool-holder is released or drawn backward by a positive movement, and a spring is employed to press the toolholder forward as it grasps the tool, and the exterior case is made of two principal parts, the lower end of which is adapted to being grasped by the hand, and the upper end is provided with an adjustable tubular case surrounding a helical spring, by The adjustment of which more or less tension can be applied to the spring, and when the upper part of the case is swung or deected at an angle to the lower part of the case, the tubular case around the spring causes such spring to be distended, and hence the parts are returned to a normal position with a rapid positive movement the moment the deecting pressure is released, thus facilitating the handling of the tool.

The helical spring and the end collars connected therewith form the flexible part of the case, and the tubular case surrounding the spring bears at one end on the forward collar to form a fulcrum when the case is swung to release the tool. In the internal mechanism there are bearing or cam surfaces that move upon each other as the parts are swung out of alinement, and an elongation is produced that releases the spring tool-holder and allows the same to open and release the tool.

The details of construction are hereinafter more particularly described and claimed.

In the drawings, Figure 1 is a longitudinal section of my improved dental handpiece. Fig. 2 is an elevation of the same. Figs. 3 to 15, inclusive, represent elevations of the 'separate parts ofthe internal mechanism,

and Fig. 16 is a partial longitudinal section of the internal parts as defiected. The iigures show the parts of about twice the usual size.

The case of my dental handpiece is preferably composed of the rigid' taper portion A, whose exterior is preferably roughened or ribbed to provide a firm hold for the hand, and the upper portion B of the case comprises the tubular case Z, the helical spring ct, the collar et', and screw-collar a2. The collar ct' receives within it one end of the helical spring a, andthe other end of said spring extends over the forward end of the collar a2, and the ends of thespring CZ are iirmly united by solder to the collars a and a2.

The collar ct is united by a-screw-coupling at 2 to the taper portion A, and the back end of the collar a2 is threaded and projects for receiving the sleeve at the end of the flexible covering for the shaft of the dental engine, and the tubular case Z has a nut at one end which screws upon the collar d2 and surrounds the spring ct and extends into the enlarged end of the collar a', and the end of said oase Z bears against said collar, and the said tubular case Z can be screwed along upon the collar d2 to strain the helical spring a and apply any desired tension thereon. The case Z also protects the hand from contact with the spring ct and acts to exclude dust from the internal parts.

Figs. 3 and et show separately the Asleeves b.

b, that screw'together and are received within the rigid taper-case A. The right-hand or back end of the sleeve b' is reduced, and a hard-metal collar b2, fitting over said end, is held between the end of the case A and an internal rib on the collar a', and this collar b2 forms a stop -around the back 'end of the sleeve b', thus holding the sleeves b b within IOO the tubular case andr preventing end motion, but allowing them to be revolved freely. The clamping-nut g prevents the collar a' turning and secures the parts after they have been adjusted.

The forward end of the sleeve b is tapering to conform to the interior of the case A, and it is also internally tapered to act on the holding-jaws d', Fig. 5, and these jaws receive and hold the tool. These jaws d are made with an open center to receive the tool, and the longitudinal slots between the jaws allow them to spring, and they are tapered at both ends, the forward ends being received into the tapering sleeve b and the back ends into the recessed forward end of the sleeve c', Figs. 1 and 7. The adjusting-stem f has a threaded portion 12 and screws into the split end of the sleeve c', Figs. land 7. This stem f has a screw-driver notch 13 at one end.

The rod 7L from the dental-engine shaft is connected by a pin 17 with the collar o. A screw stem or rod 'n is provided with a head n and adjacent neck, there being a flaring hole through the head n'. This head is received within the collar d, behind the internal rib 11, and a pin 1G passes through the flaring hole and connects the head and collar together, and the end of the collar o' is provided with curved bearing-faces 19. A headblock o, that surrounds the rod n, is provided with curved bearing-faces 18, receiving or coming against the faces 19, and the block 0 fits into and bears against the end of the sleeve b. This rod n screws into the sleeve m and around the rod n within the sleeve b', and between the sleeve 'm and inner end of the sleeve b and the block ois the expansive spring It, whose action is to force the sleeve m forward, and so hold the faces 18 and 19 tightly together and the parts axially in line, the head n bearing against the rib 11. The opposite ends Aof the sleeves m and e are notched, and the ends of thethrust-piece fr are reduced to form tongues that are received in said notches, the tongues at one end bearing against the threaded stem f, and the other tongue is notched to receive and bear against the reduced end of the rod n.

The parts are put together in approximately the following manner and order: The rod n and collar c' are connected by the pin 16, with the head frt/ bearing against the rib 11 from within, and the rod h and collar c' are connected together by the pin 17. The head-block o is slipped over the rod n and the ring b2 over the end of the sleeve b', and then the sleeve b and ring b2 are passed over the rod n and block o. The spring 7c is passed into the sleeve Z/ and over the rod n, and the sleeve m screwed on the rod n to compress the spring k and draw the parts together. The screw-stem f is inserted in the sleeve e'. The tool-holder d is now inserted in the sleeve b, and the sleeve e and thrust-piece r inserted therein, following the tool-holder. The sleeves b and b' are brought together with the ends of the thrustpiece in the notches of the sleeves c' and m, and they are screwed together. A screwdriver can be inserted in place of an operating-tool, and it engages the stem f at its notch 13, and by rotating said stem in the sleeve e the parts are adjusted in their axial line to provide for slight variations in the diameters of the tool-Shanks, so as to bring sufficient pressure by the holding-jaws to grip the operating-tool C. This adjustment also provides for wear of the parts. The flexible dental-en gine shaft rotates the rod h and the parts within the connected cases A and B that extend from such shaft to the tool-holder.

To release the operating-tool from the grip of the holding-jaws, it is only necessary to bring one part of the case at an angle to the other part and thereby produce an elongation of the axis of the handpiece. This is accomplished by one hand, while holding the handpiece, by a pressure of the thumb and iingers bending the helical spring a, out of line with the tapering case A. "When the handpieceis thus deflected in the hand, the end of the tubular case Z rocks upon the collar rt as a f ulcrum, the helical spring ct is bent and distended, and the rod 71, is'swung into approximately t-he position shown in Fig. 16. This operation disturbs the alineinent of the inp ternal mechanism and causes the curved bearing-face 19 of the collar c to move upon the curved bearing-surface 18 of the head-block o and so draw the rod n and head n and sleeve m longitudinally, compressing the spring 7.: and releasing the parts r e', so that the toolholder is free to expand and release the tool.

When the pressure of the hand is released, the spring returns the parts to their normal positions of al inement, and by this movement the pressure upon the holding-j aws is restored and the operating-tool firmly gripped by the tool-holder.

It is obvious that suitable equivalent means may be employed to connect the head 'n' or rod 7L, or both of them, to the collar c to cause the said parts to-rotate together.

I claim as my invention- 1. The combination in a dental handpiece, of a case adapted to being held in the hand, a tool-holder within the case, a driving-shaft adapted to being connected to the flexible shaft of the dental engine, an internal spring surrounding a portion of the driving-shaft for giving end movement to the tool-holder to grasp the tool, and devices having opposing curved bearing-faces adapted to rock on one another and acting to compress the spring and positively move a portion of the drivingshaft longitudinally to remove the pressure on the tool-holder and permit the same to expand and release the tool when the rear part of the shaft is swung or deflected, substantially as set forth.

2. The combination in a dental handpiece, of a case adapted to be grasped by the hand, a spring connected with the rear end of such case, a tubular case surrounding the spring,

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and bearing at one end against the rear end i of the case whereby the spring is distended when the rear part of the case is deflected out of line with the hand portion of the case and such tubular case is restored into line with the case by the action of the spring, substantially as set forth.

3. The combination in a dental handpiece, of a case adapted to being grasped by the hand and having a collar at its rear end, a drivingshaft adapted to being connected to the ilexible shaft of the dental engine, a screw-collar surrounding and sliding upon such shaft, a spring connected at one end with the screwcollar and at the other end to the collar of the handpiece, a tubular case around the spring with a nut at one end upon the screwcollar for adjusting the tension of the spring and devices having opposing curved bearingfaces for allowing the driving-shaft and tube l. to be turned or deflected into an angular position to the hand portion of the case and restored into line by the action of the spring, substantially as set forth.

4. The combination in a dental handpiece, of a case adapted to being grasped by the hand, a tool-holder to receive and grasp the tool by an end movement, a driving-shaft and an upper portion to the case around such drivingshaftand adapted to being deflected with that shaft into an angular position to the case, a connection from the driving-shaft to the tool-holder for rotating the same, an internal spring surrounding a portion of the driving-shaft for causing the tool-holder to grasp the tool and devices having opposing curved bearing-faces adapted to rock on one another and intervening between a portion of the driving-shaft and the spring for acting upon such spring to compress the same and to simultaneously and positively move a portion of the drivin g-shaft longitudinally to remove the pressure on the tool-holder and permit the same to expand and release the tool when the shaft is deflected, substantially as set forth.

5. The combination in a dental handpiece, of acase adapted to being grasped by the hand, a tool-holder to receive and grasp the tool by an end movement, a driving-shaft and an upper portion to the case around such drivingshaft and adapted to being deflected with that shaft into an angular position to the case, a connection from the driving-shaft to the toolholder for rotating the same,an internal spring surrounding a portion of the driving-shaft for causing the tool-holder to grasp the tool and devices having opposing curved bearingfaces adapted to rock on one another and intervening between a portion of the drivingshaft and the spring for acting upon such spring to compress the same and to simultaneously and positively move a portion of the driving-shaft longitudinally to remove the pressure on the tool-holder and permit the same to expand and release the tool when the shaft is deflected, and an adjustment between the tool-hold er and the spring for varying the action and adapting the tool-holder to different sizes of tools, substantially as set forth.

6. The combination in a de ntal handpiece with the spring tool-holding jaws tapering at both ends, of a sleeve receiving the spring tool-holder, an internal sleeve adjacent to the rear end of the spring tool-holder, a threaded adj usting-stem within the internal sleeve, a thrust-piece against which the adj ustin g-stem acts, the dental-engine shaft and mechanism intervening between the l-hrustpiece and such shaft for applying or relieving the pressure upon the thrust-piece, substantially as set forth.

7. In a dental handpiece, the combination with the rigid case A and collar a having an internal rib, of the sleeve hhaving a reduced end, the hard-metal collar b2 at the end of the case A and sleeve b and between the same and the rib of the collar a', substantially as set fort-h.

8. In a dental handpiece, the combination with the sleeve b' and the rod h from the dental-engine shaft, of the collar c', means for connecting the same to the rod h, the rod n, its head n within the collar c' and a pin passing loosely through the head and intoxthe collar c to connect said parts, a head-block 0 around the rod n, the collar c and. head-block o having adjacent curved bearing-faces whereby said rod h may be rocked or deflected from its axial line, and an end movement given to the rod fn, substantially as set forth.

9. In a dental handpiece, the combination with the sleeve b and the rod 7i from the den- IOC tal-engine shaft, of the collar c connected to head n having a flaring hole and adjacent neck and bearing Within the collar c' against the rib 11, the pin 1G passing through said collar and head, the head-block o received within the end of the sleeve b and having curved bearing-faces 18 that bear on the faces 19 and the helical expansion-spring 7a around the rod a and acting against the sleeve m and inner end of the sleeve b and block o to hold the faces 18 and 19 together tightly and the parts axially in line, substantially as set forth.

lO. In a dental handpiece, the combination with the sleeves b ZJ' and the spring toolholder d', of the notched sleeves c/ and m', the threaded adjusting-stem f Within the sleeve e and having a screw-driver notch 13, the rod n threaded at one end and screwing into the sleeve m, the thrust-piece r having reduced ends received within the notches of the sleeves e and m and bearing at its ends upon the ends of the rod n and stem f respectively, the parts being adjusted longitudinally by the rotation of the stem f, by an instrument inserted in theroom of the'operat-ing-tool, substantially as set forth.

11. In a dental handpiece, the combination IZO with the rigid case A, oi' the helical spring a., the collar ce having a threaded coupling 2 by which it is connected to the case Aand an enlarged end recessed, the collar a2 threaded at the back end and fitting within the spring a, the ends of the helical spring being permanently connected to the collars, and a tubular case Z screwing at one end upon the collar a2 and at the other end fitting within and bearing against the enlarged end of the collar a' and covering the spring d, substantially as and for the purposes set forth.

12. Ina dental hand piece, the combination with the sleeve b' and rod 7L 'from the dentalengine shaft, of the collar c' having an internal rib 11 and adjacent curved bearing-faces 19 at one end thereof, the head-block o received Within the end of the sleeve b and having curvedV bearing-faces 18 bearing on the faces 19, the rod n, lthe head n thereon and Within the collar c bearing upon the rib 11, a helical sprin g for drawing the part-s into axial line and means for connecting the head n or rod h or both to the collar c to cause them to rotate together, substantiallyT as set forth.

Signed by inc this 27th day of December, A. D. 1895. V

JOHANNES TH. PEDERSEN. Titnessesz GEO. T. PINCKNEY, HAROLD SERRELT.. 

